Rails - Jun 2008 - What is Best Way of Tackling Rising Data Anomalies

Here is a problem: while the user is adding , deleting and modifying
data , data anomalies can arise, for example take the the two table A, B
which are joined by the intermediate join table A_B:

[A]
id:integer
name:string

[A_B]
a_id:integer
b_id:integer

[B]
id:integer
name:string


Now I have in A''s model file:
has_many :a_b, :dependent => :destroy

and in B''s model file :
has_many :a_b, :dependent => :destroy

Apparently sometimes the dependent destroy directive is not taking
place.

For example B is deleted from the database but the deleted record''s id
remains in A_B. This causes nil.nilclass exceptions ; what is the best
way of handling this? [more explanation see 1]

How to gracefully tackle these data anomalies that may arise?

{1}Elaboration :

example
[A]
[1:TestA]

[A_B]
[1,1]

[B]
[1:TestB]

--
Now despite the model file directive sometimes [B] is empty but [A_B]
remains and when I try to access A.A_B.name I get a nil class exception.
Currently when I encounter this errant intermediate record I delete and
move on but any other features if they exist would be great to learn
(sorry if my expectations are through the roof, but ROR is great)
-- 
Posted via http://www.ruby-forum.com/.

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>
> --
> Now despite the model file directive sometimes [B] is empty but [A_B]
> remains and when I try to access A.A_B.name I get a nil class exception.
> Currently when I encounter this errant intermediate record I delete and
> move on but any other features if they exist would be great to learn
> (sorry if my expectations are through the roof, but ROR is great)
As far as I''m concerned, if you want a cast iron guarantee that your
foo_id columns are just dangling then that guarentee has to be
provided by the database (ie a foreign key constraint)

Fred
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